Usually, when you have the post you want to delete, you use the three little dots below it to the right (at least on my phone) for extra options and there (for me) it says "delete globally". Hope this helps.

It works!! Thank you very much for the help, I am often overwhelmed by technical stuffs, but often glad when learned something. I even learned to edit now haha thanks

You're very welcome! I'm glad it helped you. 😊 And yay for learning new things.